Conventional apparatus used in the assembly of emergency brake cable systems often require more than one person and more than one station on an assembly line for adequate installation and tensioning. Once the emergency brake cable system is initially installed, one assembly worker typically first tensions the system to the desired level, at which the voids are removed from the cable and the conduits through which the cable runs. At a second assembly position, a second assembly worker then typically reduces the tension in the system in a variety of ways so that the emergency brake cable system is not causing the brakes to be engaged. The existing systems require more than one assembly worker and more than one station, and thus are a relatively expensive endeavor.
A further limitation of the existing brake cable system installation technology is that the tension in the cable system is typically measured by indirect methods, such as strain gauges and other types of transducers. This means that the actual tension in the brake cable system, which is important to the proper functioning of the emergency brake, is at best characterized and not directly known during the assembly process. This indirect tension measurement has limited measurement accuracy, and thus causes there to be a relatively wide variation in the ultimate tension at which the emergency brake cable system is assembled in a vehicle. This creates unwanted variations in the emergency brake cable system operation on the finished vehicle.
Some other emergency brake tensioning systems have reduced the human element involved in the process by use of automated mechanisms. However, these systems use hydraulics or pneumatics as part of the process, which may lead to maintenance problems, cleanliness issues, tension measurement inaccuracies, and generally to a more complicated and inconvenient system.
What is needed is an emergency brake cable tensioning method and apparatus that overcomes the above issues, and allows fewer resources to be used in tensioning the cable system, thus saving money in the assembly process and ultimately allowing automobiles to be manufactured more efficiently. In addition, what is needed is an emergency brake cable tensioning method and apparatus that allows the direct measurement of the tension of the brake cable system during assembly to allow the accurate tensioning of the emergency brake cable system for proper performance in the finished vehicle. These and other advantages provided by embodiments of the present invention will be recognized from the following descriptions of embodiments of the invention.